Diagnostic

Software development agreements: why paying for the code does not make it yours

Mexican copyright law requires an assignment that is written, for consideration, and for a term. Without one, the code your company paid for may still belong to whoever wrote it.

LEXURE Industrial and Intellectual Property Practice Team 7 min read Regulatory status verified in 2026

A tech­nol­ogy com­pany’s value lies largely in the code it exploits. That is why it is sur­pris­ing how many cannot prove that the code belongs to them. Paying the devel­oper’s invoice does not trans­fer own­er­ship; that requires a con­tract that meets the require­ments of the Fed­eral Copy­right Law (Ley Fed­eral del Dere­cho de Autor).

What the law requires

What the law pro­tects. A com­puter pro­gram is the orig­i­nal expres­sion, in any lan­guage or code, of a set of instruc­tions for a com­puter to per­form a task (Arti­cle 101). It is pro­tected on the same terms as a lit­er­ary work, in both source code and object code; since the amend­ment pub­lished on May 14, 2026, the text expressly includes arti­fi­cial intel­li­gence pro­grams (Arti­cle 102). Pro­tec­tion arises once the work is fixed in a mate­rial medium and does not depend on reg­is­tra­tion (Arti­cles 5 and 162), although reg­is­tra­tion pro­vides public notice and cer­tainty about who owns it.

The assign­ment must be writ­ten, for con­sid­er­a­tion, and tem­po­rary. Every trans­fer of eco­nomic rights of author­ship is for con­sid­er­a­tion and tem­po­rary, and the con­tracts through which those rights are trans­ferred must invari­ably be exe­cuted in writ­ing; oth­er­wise, they are null and void by oper­a­tion of law (Arti­cle 30). The author has a non-waiv­able right to a pro­por­tional share of the rev­enue or to a fixed and deter­mined fee (Arti­cle 31). For the trans­fer to be effec­tive against third par­ties, it must be recorded with the Public Copy­right Reg­istry (Reg­istro Público del Dere­cho de Autor), under Arti­cle 32.

The term. Absent an express stip­u­la­tion, every trans­fer is deemed to be for five years, and only excep­tion­ally may it be agreed for more than fif­teen (Arti­cle 33). Soft­ware has a spe­cial rule: the term of an assign­ment of rights over com­puter pro­grams is not sub­ject to lim­i­ta­tion (Arti­cle 103, second para­graph). Even so, the assign­ment should state its term, because if the con­tract is silent, the gen­eral pre­sump­tion applies.

Future works. Only spe­cific future works whose char­ac­ter­is­tics are set out in the con­tract may be con­tracted. A blan­ket trans­fer of future works is void, as are stip­u­la­tions by which the author under­takes not to create any work (Arti­cle 34). A master agree­ment that assigns “every­thing the devel­oper cre­ates” with­out describ­ing it is vul­ner­a­ble.

Employ­ees and con­trac­tors are not treated the same. Soft­ware cre­ated by employ­ees in the per­for­mance of their duties or fol­low­ing the employer’s instruc­tions belongs to the employer, unless oth­er­wise agreed (Arti­cle 103). For other works cre­ated within an employ­ment rela­tion­ship, the rule dif­fers: with a writ­ten indi­vid­ual employ­ment con­tract and no agree­ment on the matter, the rights are divided equally; with­out a writ­ten con­tract, they belong to the employee (Arti­cle 84). For exter­nal devel­op­ers, the route is the com­mis­sioned work (obra por encargo): the person who com­mis­sions the work holds own­er­ship, unless oth­er­wise agreed (Arti­cle 83), but the con­tract terms must be clear and pre­cise, and in case of doubt the inter­pre­ta­tion most favor­able to the author pre­vails (Arti­cle 83 bis, second para­graph).

What to do and by when

  1. Pre­pare an inven­tory of your plat­form’s com­po­nents and who devel­oped them: employ­ees, free­lancers, devel­op­ment firms, or founders before the com­pany was incor­po­rated.
  2. For each exter­nal devel­oper, sign a writ­ten con­tract that states that the engage­ment is a com­mis­sioned work and, in addi­tion, an express assign­ment of eco­nomic rights with its con­sid­er­a­tion and term.
  3. Describe in the con­tract the future work being com­mis­sioned: mod­ules, fea­tures, deliv­er­ables, and repos­i­tory. Avoid blan­ket word­ing.
  4. For employ­ees, verify that there is a writ­ten indi­vid­ual employ­ment con­tract that describes their devel­op­ment duties, so there is no doubt that Arti­cle 103 applies.
  5. For­mal­ize in writ­ing the assign­ment of the code the founders wrote before the com­pany existed.
  6. Record the rel­e­vant assign­ments with the Public Copy­right Reg­istry, espe­cially before a fund­ing round or a sale.
  7. Keep evi­dence of author­ship and deliv­ery: repos­i­tory his­tory, accep­tance records, and proof of pay­ment.
  8. Inven­tory the open source com­po­nents and third-party licenses your plat­form uses, because those pieces do not belong to you and their terms of use are also reviewed in an invest­ment.

Recommendations to mitigate risk

What your com­pany risks is own­er­ship of the code. An oral assign­ment is void, and one that does not state a term is pre­sumed to be for five years. A free­lancer with­out a writ­ten con­tract retains the eco­nomic rights over what they wrote, so they can object to its exploita­tion, demand com­pen­sa­tion, or nego­ti­ate with a third party. If the assign­ment is not recorded, it has no effect against third par­ties, which weak­ens the com­pany’s posi­tion against anyone claim­ing a prior right. In a pre-invest­ment due dili­gence review, an incom­plete chain of title usu­ally trans­lates into clos­ing con­di­tions, pur­chase price hold­backs, or rep­re­sen­ta­tions backed by indem­ni­ties from the founders. Fixing it later costs more: a devel­oper who has already ended their rela­tion­ship with the com­pany has no incen­tive to sign a retroac­tive assign­ment with­out new con­sid­er­a­tion.

Self-assessment

Answer yes or no about your own com­pany.

  1. Do you have a writ­ten con­tract with each exter­nal devel­oper who has worked on your plat­form?
  2. Do those con­tracts include an express assign­ment, with con­sid­er­a­tion and a term?
  3. Did the founders assign to the com­pany, in writ­ing, the code they wrote before incor­po­rat­ing it?
  4. Do all your employed devel­op­ers have a writ­ten indi­vid­ual employ­ment con­tract?
  5. Are the com­mis­sioned works described in the con­tract, rather than assigned in blan­ket terms?
  6. Have you recorded the rel­e­vant assign­ments with the Public Copy­right Reg­istry?
  7. Do you have an inven­tory of the open source and third-party com­po­nents your plat­form uses?

How we approach it at LEXURE

We rebuild the chain of title of your soft­ware, com­po­nent by com­po­nent, iden­tify the gaps, and close them with com­mis­sion­ing agree­ments, assign­ments, and, where advis­able, their reg­is­tra­tion. We deliver a file your com­pany can show an investor or a buyer to prove that the code is yours.

If your com­pany depends on soft­ware that others helped build, sched­ule a diag­nos­tic meet­ing with us and let us review your chain of title.

Schedule a diagnostic meeting See our service lines

Legal basis

  1. Federal Copyright Law (Ley Federal del Derecho de Autor), last amended DOF May 14, 2026, Articles 5, 30, 31, 32, 33, 34, 83, 83 bis, 84, 101, 102, 103, and 162. Current text (opens in a new tab)

This note is for information only and describes the law in force on the verification date. It is not legal advice on a specific matter. It is a translation of the Spanish original: Mexican law is published in Spanish, and the official Spanish texts prevail.

Keep reading

Related notes.

See all notes